Voltage converter for medical devices

ABSTRACT

A voltage converter for medical devices includes a switch capacitor converter core including a plurality of power transistor switches configured to receive an input voltage and output an output voltage; a switch driver connected with the switch capacitor converter core and configured to turn on corresponding power transistor switches in the switch capacitor converter core so as to supply power to a load receiving the output voltage; a switch signal router connected with the switch driver and configured to selectively transmit signals required by the switch driver; a gain selection decoder connected with the switch signal router; a gain controller connected with the gain selection decoder, the gain selection decoder being configured to decode gain selection instructions transmitted from the gain controller; an input adjusting device connected with the gain controller and configured to receive the input voltage and a reference voltage, to indicate relationship between the input voltage and the reference voltage, and to transmit the relationship to the gain controller; and an output adjusting device connected with the gain controller and configured to receive the output voltage and the reference voltage, to indicate relationship between the output voltage and the reference voltage, and to transmit the relationship to the gain controller.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application claims the benefit of U.S. non-provisional patentapplication Ser. No. 15/970,898 filed on May 4, 2018, which is adivisional application of U.S. non-provisional patent application Ser.No. 15/372,410 filed on Dec. 8, 2016, now U.S. Pat. No. 10,016,611; thecontents of which is hereby incorporated by reference.

FIELD OF THE PATENT APPLICATION

The present patent application generally relates to medical electronicsand more specifically to a voltage converter for medical devices.

BACKGROUND

Implantable medical devices have been applied more and more widely inmodern medicine. Because of its unique applications, an implantablemedical device generally requires the power supply that supplies powerto it to be small volume, low power and high power transfer efficiency.Not only so, the implantable medical device but also generally hasmultiple working modes, such as a sleep mode, a measurement mode, a datatransmission mode, and so on. In each different working mode, the sameimplantable medical device typically has a different requirement on thepower supply that supplies power to it.

Voltage converter is an important component of a power supply system ofan implantable medical device. Conventional voltage converters usuallycannot effectively satisfy different requirements of the implantablemedical device in different working modes on the output voltage and theload values, which are in a relatively wide range. In addition, toimprove the configurability, conventional voltage converters usuallyhave relatively complicated circuits, relatively large chip areas,relatively high power consumption, and relatively low system workingefficiency, and therefore are not suitable for supplying power tomedical devices.

SUMMARY

The present patent application is directed to a voltage converter formedical devices. In one aspect, the voltage converter includes: a switchcapacitor converter core including a plurality of power transistorswitches configured to receive an input voltage and output an outputvoltage; a switch driver connected with the switch capacitor convertercore and configured to turn on corresponding power transistor switchesin the switch capacitor converter core so as to supply power to a loadreceiving the output voltage; a switch signal router connected with theswitch driver and configured to selectively transmit signals required bythe switch driver; a gain selection decoder connected with the switchsignal router; a gain controller connected with the gain selectiondecoder, the gain selection decoder being configured to decode gainselection instructions transmitted from the gain controller; an inputadjusting device connected with the gain controller and configured toreceive the input voltage and a reference voltage, to indicaterelationship between the input voltage and the reference voltage, and totransmit the relationship to the gain controller; an output adjustingdevice connected with the gain controller and configured to receive theoutput voltage and the reference voltage, to indicate relationshipbetween the output voltage and the reference voltage, and to transmitthe relationship to the gain controller; a clock generator connectedwith the switch signal router, the gain controller and the outputadjusting device; and a counter connected with the gain controller. Theinput adjusting device includes an adaptive ADC configured to determinea required conversion gain ratio based on the input voltage and thereference voltage, and a control logic circuit connected with theadaptive ADC and configured to control the adaptive ADC. The outputadjusting device includes a plurality of comparators and a control logiccircuit connected with the comparators. The gain controller isconfigured to control the conversion gain ratio required by the switchcapacitor converter core according to information provided by the inputadjusting device and the output adjusting device, the conversion gainratio being the ratio between the output voltage and the input voltage.When the output voltage is in a threshold range below the referencevoltage, the gain controller is turned off, and switching frequency ofthe switch capacitor converter core is adjusted by discrete amountsbased on a DFS (Discrete-frequency Scaling) algorithm so that the outputvoltage gradually approaches the reference voltage. When the outputvoltage is equal to or greater than the reference voltage, the switchcapacitor converter core stops its switching operations. When the outputvoltage is lower than the reference voltage, the switch capacitorconverter core is configured to resume its switching operations.

The switch capacitor converter core may include a plurality of powertransistor switches and a pump capacitor, and the conversion gain ratioprovided by the switch capacitor converter core may be 1/2, 2/3, 1, 3/2or 2.

The adaptive ADC in the input adjusting device may include a comparatorand a plurality of latches, the latches being connected with thecomparator and configured to generate data of a predetermined number ofdigits according to a result from the comparator, the data describingratio between the reference voltage and the input voltage, and beingused to set the required conversion gain ratio.

The gain controller may include a digital circuit; when the outputvoltage is below the threshold range below the reference voltage, thedigital circuit may be configured to, through adjusting the conversiongain ratio, adjust the output voltage by a large amount.

The counter may be configured to count a predetermined number of clockperiods every time after the switching frequency of the switch capacitorconverter core is changed, so that there is sufficient time for theoutput voltage to respond to the change.

The clock generator may include a comparator; a logic circuit connectedwith the comparator and configured to drive the comparator; and a clocksignal generator connected with the logic circuit and configured tooutput two clock signals. The two clock signals may be transmitted tothe switch signal router and the switch driver, and further configuredto control the switch capacitor converter core.

In another aspect, the present patent application provides a voltageconverter for medical devices including: a switch capacitor convertercore including a plurality of power transistor switches configured toreceive an input voltage and output an output voltage; a switch driverconnected with the switch capacitor converter core and configured toturn on corresponding power transistor switches in the switch capacitorconverter core so as to supply power to a load receiving the outputvoltage; a switch signal router connected with the switch driver andconfigured to selectively transmit signals required by the switchdriver;

a gain selection decoder connected with the switch signal router; a gaincontroller connected with the gain selection decoder, the gain selectiondecoder being configured to decode gain selection instructionstransmitted from the gain controller; an input adjusting deviceconnected with the gain controller and configured to receive the inputvoltage and a reference voltage, to indicate relationship between theinput voltage and the reference voltage, and to transmit therelationship to the gain controller; an output adjusting deviceconnected with the gain controller and configured to receive the outputvoltage and the reference voltage, to indicate relationship between theoutput voltage and the reference voltage, and to transmit therelationship to the gain controller; a clock generator connected withthe switch signal router, the gain controller and the output adjustingdevice; and a counter connected with the gain controller. The inputadjusting device includes an adaptive ADC configured to determine arequired conversion gain ratio based on the input voltage and thereference voltage, and a control logic circuit connected with theadaptive ADC and configured to control the adaptive ADC. The outputadjusting device includes a plurality of comparators and a control logiccircuit connected with the comparators. The gain controller isconfigured to control the conversion gain ratio required by the switchcapacitor converter core according to information provided by the inputadjusting device and the output adjusting device, the conversion gainratio being the ratio between the output voltage and the input voltage.The gain controller includes a digital circuit. When the output voltageis out of a threshold range around the reference voltage, the digitalcircuit is configured to, through adjusting the conversion gain ratio,adjust the output voltage by a large amount. When the output voltage isin a threshold range around the reference voltage, the gain controlleris turned off, and switching frequency of the switch capacitor convertercore is adjusted by discrete amounts based on a DFS (Discrete-frequencyScaling) algorithm so that the output voltage gradually approaches thereference voltage.

The switch capacitor converter core may include a plurality of powertransistor switches and a pump capacitor, and the conversion gain ratioprovided by the switch capacitor converter core may be 1/2, 2/3, 1, 3/2or 2.

The adaptive ADC in the input adjusting device may include a comparatorand a plurality of latches, the latches being connected with thecomparator and configured to generate data of a predetermined number ofdigits according to a result from the comparator, the data describingratio between the reference voltage and the input voltage, and beingused to set the required conversion gain ratio.

The clock generator may include a comparator; a logic circuit connectedwith the comparator and configured to drive the comparator; and a clocksignal generator connected with the logic circuit and configured tooutput two clock signals. The two clock signals may be transmitted tothe switch signal router and the switch driver, and further configuredto control the switch capacitor converter core.

In yet another aspect, the present patent application provides a voltageconverter for medical devices. The voltage converter includes: a switchcapacitor converter core including a plurality of power transistorswitches configured to receive an input voltage and output an outputvoltage; a switch driver connected with the switch capacitor convertercore and configured to turn on corresponding power transistor switchesin the switch capacitor converter core so as to supply power to a loadreceiving the output voltage; a switch signal router connected with theswitch driver and configured to selectively transmit signals required bythe switch driver; a gain selection decoder connected with the switchsignal router; a gain controller connected with the gain selectiondecoder, the gain selection decoder being configured to decode gainselection instructions transmitted from the gain controller; an inputadjusting device connected with the gain controller and configured toreceive the input voltage and a reference voltage, to indicaterelationship between the input voltage and the reference voltage, and totransmit the relationship to the gain controller; an output adjustingdevice connected with the gain controller and configured to receive theoutput voltage and the reference voltage, to indicate relationshipbetween the output voltage and the reference voltage, and to transmitthe relationship to the gain controller; a clock generator connectedwith the switch signal router, the gain controller and the outputadjusting device; and a counter connected with the gain controller.

The input adjusting device may include an adaptive ADC configured todetermine a required conversion gain ratio based on the input voltageand the reference voltage, and a control logic circuit connected withthe adaptive ADC and configured to control the adaptive ADC.

The output adjusting device may include a plurality of comparators and acontrol logic circuit connected with the comparators.

The gain controller may be configured to control the conversion gainratio required by the switch capacitor converter core according toinformation provided by the input adjusting device and the outputadjusting device, the conversion gain ratio being the ratio between theoutput voltage and the input voltage.

When the output voltage is in a threshold range below the referencevoltage, the gain controller may be turned off, and switching frequencyof the switch capacitor converter core may be adjusted by discreteamounts based on a DFS (Discrete-frequency Scaling) algorithm so thatthe output voltage gradually approaches the reference voltage.

When the output voltage is equal to or greater than the referencevoltage, the switch capacitor converter core may stop its switchingoperations.

When the output voltage is lower than the reference voltage, the switchcapacitor converter core may be configured to resume its switchingoperations.

The switch capacitor converter core may include a plurality of powertransistor switches and a pump capacitor, and the conversion gain ratioprovided by the switch capacitor converter core may be 1/2, 2/3, 1, 3/2or 2.

The adaptive ADC in the input adjusting device may include a comparatorand a plurality of latches, the latches being connected with thecomparator and configured to generate data of a predetermined number ofdigits according to a result from the comparator, the data describingratio between the reference voltage and the input voltage, and beingused to set the required conversion gain ratio.

The clock generator may include a comparator; a logic circuit connectedwith the comparator and configured to drive the comparator; and a clocksignal generator connected with the logic circuit and configured tooutput two clock signals. The two clock signals may be transmitted tothe switch signal router and the switch driver, and further configuredto control the switch capacitor converter core.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a block diagram of a voltage converter for medical devices inaccordance with an embodiment of the present patent application.

FIG. 2A is block diagram of an input adjusting device of the voltageconverter depicted in FIG. 1.

FIG. 2B is block diagram of an output adjusting device of the voltageconverter depicted in FIG. 1.

FIG. 3 is block diagram of a clock generator of the voltage converterdepicted in FIG. 1.

DETAILED DESCRIPTION

Reference will now be made in detail to a preferred embodiment of thevoltage converter for medical devices disclosed in the present patentapplication, examples of which are also provided in the followingdescription. Exemplary embodiments of the voltage converter for medicaldevices disclosed in the present patent application are described indetail, although it will be apparent to those skilled in the relevantart that some features that are not particularly important to anunderstanding of the voltage converter for medical devices may not beshown for the sake of clarity.

Furthermore, it should be understood that the voltage converter formedical devices disclosed in the present patent application is notlimited to the precise embodiments described below and that variouschanges and modifications thereof may be effected by one skilled in theart without departing from the spirit or scope of the protection. Forexample, elements and/or features of different illustrative embodimentsmay be combined with each other and/or substituted for each other withinthe scope of this disclosure.

FIG. 1 is a block diagram of a voltage converter for medical devices inaccordance with an embodiment of the present patent application.Referring to FIG. 1, the voltage converter for medical devices includesa switch capacitor converter core 101 that includes a plurality of powertransistor switches configured to receive an input voltage and output anoutput voltage; a switch driver 103 connected with the switch capacitorconverter core 101 and configured to turn on corresponding powertransistor switches in the switch capacitor converter core 101 so as tosupply power to a load 104 receiving the output voltage; a switch signalrouter 105 connected with the switch driver 103 and configured toselectively transmit signals required by the switch driver 103; a gainselection decoder 107 connected with the switch signal router 105; again controller 109 connected with the gain selection decoder 107, thegain selection decoder 107 being configured to decode gain selectioninstructions transmitted from the gain controller 109; an inputadjusting device 111 connected with the gain controller 109 andconfigured to receive the input voltage and a reference voltage, toindicate relationship between the input voltage and the referencevoltage, and to transmit the relationship to the gain controller 109; anoutput adjusting device 113 connected with the gain controller 109 andconfigured to receive the output voltage and the reference voltage, toindicate relationship between the output voltage and the referencevoltage, and to transmit the relationship to the gain controller 109; aclock generator 115 connected with the switch signal router 105, thegain controller 109 and the output adjusting device 113; and a counter117 connected with the gain controller 109.

FIG. 2A is block diagram of an input adjusting device of the voltageconverter depicted in FIG. 1. Referring to FIG. 2A, in this embodiment,the input adjusting device 111 includes an adaptive ADC 201 configuredto determine a required conversion gain ratio based on the input voltageand the reference voltage, and a control logic circuit 203 connectedwith the adaptive ADC 201 and configured to control the adaptive ADC201. Referring to FIG. 1 and FIG. 2A, in this embodiment, the adaptiveADC 201 in the input adjusting device 111 includes a comparator 204 anda plurality of latches 205. The latches 205 are connected with thecomparator 204 and configured to generate data of a predetermined numberof digits according to a result from the comparator 204. In thisembodiment, the predetermined number of digits is 3. The 3-digit datadescribes ratio between the reference voltage and the input voltage, andis used to set the required conversion gain ratio. When the inputvoltage changes by a small amount, the 3-digit data generated by thelatches 205 remains unchanged. When the input voltage changes by arelatively large amount, the 3 digit data generated by the latches 205changes so as to change the conversion gain ratio.

FIG. 2B is block diagram of an output adjusting device of the voltageconverter depicted in FIG. 1. Referring to FIG. 2B, in this embodiment,the output adjusting device 113 includes a plurality of comparators 211and a control logic circuit 213 connected with the comparators 211. Eachof the comparators 211 in the output adjusting device 113 includes aread amplifier. The use of the read amplifier helps with furtherlowering the system power consumption.

Referring to FIG. 1, the gain controller 109 is configured to controlthe conversion gain ratio required by the switch capacitor convertercore 101 according to information provided by the input adjusting device111 and the output adjusting device 113. The conversion gain ratio isthe ratio between the output voltage and the input voltage.

In this embodiment, when the output voltage is sufficiently close to thereference voltage, for example, when the output voltage is in athreshold range below the reference voltage, the gain controller 109 isturned off, and the switching frequency of the switch capacitorconverter core 101 is adjusted by discrete amounts based on a DFS(Discrete-frequency Scaling) algorithm so that the output voltagegradually approaches the reference voltage and fine-tuning of the outputvoltage is realized. When the output voltage reaches or exceeds thereference voltage, the switch capacitor converter core 101 stops itsswitching operations. When the output voltage is lower than thereference voltage, the switch capacitor converter core 101 is configuredto resume its switching operations.

More specifically, referring to FIG. 1, the switch capacitor convertercore 101 includes a plurality of power transistor switches and a pumpcapacitor. The conversion gain ratio may be greater or less than 1. Inthis embodiment, the conversion gain ratio provided by the switchcapacitor converter core 101 may be 1/2, 2/3, 1, 3/2 or 2. The gaincontroller 109 includes a digital circuit. When the output voltage isout of a predetermined range (the reference voltage±a predeterminedthreshold), the digital circuit, through adjusting the conversion gainratio, adjusts the output voltage by a relatively great amount,therefore realizing rough adjustment of the output voltage throughadaptive power control.

When the output voltage is in the predetermined range (the referencevoltage±a predetermined threshold), the gain controller 109 is turnedoff, the switching frequency of the switch capacitor converter core 101is adjusted by discrete amounts based on a DFS (Discrete-frequencyScaling) algorithm so that the output voltage is fine tuned. The counter117 is configured to count a predetermined number of clock periods everytime after the switching frequency of the switch capacitor convertercore 101 is changed, so that there is sufficient time for the outputvoltage to respond to the change. In this embodiment, the predeterminedthreshold is less than or equal to 10% of the reference voltage.

FIG. 3 is block diagram of a clock generator of the voltage converterdepicted in FIG. 1. Referring to FIG. 3, the clock generator 115includes a comparator 301; a logic circuit 303 connected with thecomparator 301 and configured to drive the comparator 301; and a clocksignal generator 305 connected with the logic circuit 303 and configuredto output two clock signals A and B. The two clock signals A and B aretransmitted to the switch signal router 105 and the switch driver 103,and further configured to control the switch capacitor converter core101. In this embodiment, the input of the comparator 301 is the outputvoltage and the reference voltage.

In another embodiment, when the output voltage is greater than thereference voltage, the switch driver 103 controls the power transistorsin the switch capacitor converter core 101 to stop switching operations.This design further lowers power consumption of the system and limitsthe overshoot of the output voltage.

In the above embodiments, the voltage converter has a small chip area,circuits with low complexity, and high configurability, implementing thecontrolling method that combines the rough adjustment (adaptive powercontrol) and the find adjustment (DFS) of the output voltage so that thevoltage converter satisfies the requirements on the output voltage andthe load in a wide range, and is especially suitable for supplying powerto medical devices. In addition, when the output voltage is greater thanthe reference voltage, the switch driver is configured to control thepower transistors of the switch capacitor converter core 101 to stopswitching operations, which not only limits overshoot of the outputvoltage, but also further decreases power consumption of the system, sothat the working efficiency of the system is improved.

While the present patent application has been shown and described withparticular references to a number of embodiments thereof, it should benoted that various other changes or modifications may be made withoutdeparting from the scope of the present invention.

What is claimed is:
 1. A voltage converter for medical devices, thevoltage converter comprising: a switch capacitor converter corecomprising a plurality of power transistor switches configured toreceive an input voltage and output an output voltage; a switch driverconnected with the switch capacitor converter core and configured toturn on corresponding power transistor switches in the switch capacitorconverter core so as to supply power to a load receiving the outputvoltage; a switch signal router connected with the switch driver andconfigured to selectively transmit signals required by the switchdriver; a gain selection decoder connected with the switch signalrouter; a gain controller connected with the gain selection decoder, thegain selection decoder being configured to decode gain selectioninstructions transmitted from the gain controller; an input adjustingdevice connected with the gain controller and configured to receive theinput voltage and a reference voltage, to indicate relationship betweenthe input voltage and the reference voltage, and to transmit therelationship to the gain controller; and an output adjusting deviceconnected with the gain controller and configured to receive the outputvoltage and the reference voltage, to indicate relationship between theoutput voltage and the reference voltage, and to transmit therelationship to the gain controller; wherein: the gain controllercomprises a digital circuit and is configured to control the conversiongain ratio required by the switch capacitor converter core according toinformation provided by the input adjusting device and the outputadjusting device, the conversion gain ratio being the ratio between theoutput voltage and the input voltage.
 2. The voltage converter formedical devices of claim 1, wherein the input adjusting device comprisesan adaptive ADC configured to determine a required conversion gain ratiobased on the input voltage and the reference voltage, and a controllogic circuit connected with the adaptive ADC and configured to controlthe adaptive ADC.
 3. The voltage converter for medical devices of claim1, wherein the output adjusting device comprises a plurality ofcomparators and a control logic circuit connected with the comparators.4. The voltage converter for medical devices of claim 1, wherein whenthe output voltage is out of a threshold range around the referencevoltage, the digital circuit is configured to, through adjusting theconversion gain ratio, adjust the output voltage by a large amount. 5.The voltage converter for medical devices of claim 4, wherein when theoutput voltage is in a threshold range around the reference voltage, thegain controller is turned off, and switching frequency of the switchcapacitor converter core is adjusted by discrete amounts based on a DFS(Discrete-frequency Scaling) algorithm so that the output voltagegradually approaches the reference voltage.
 6. The voltage converter formedical devices of claim 1, wherein the switch capacitor converter corecomprises a plurality of power transistor switches and a pump capacitor,and the conversion gain ratio provided by the switch capacitor convertercore is 1/2, 2/3, 1, 3/2 or
 2. 7. The voltage converter for medicaldevices of claim 1, wherein the adaptive ADC in the input adjustingdevice comprises a comparator and a plurality of latches, the latchesbeing connected with the comparator and configured to generate data of apredetermined number of digits according to a result from thecomparator, the data describing ratio between the reference voltage andthe input voltage, and being used to set the required conversion gainratio.
 8. The voltage converter for medical devices of claim 1 furthercomprising a clock generator connected with the switch signal router,the gain controller and the output adjusting device.
 9. The voltageconverter for medical devices of claim 8, wherein the clock generatorcomprises a comparator; a logic circuit connected with the comparatorand configured to drive the comparator; and a clock signal generatorconnected with the logic circuit and configured to output two clocksignals; the two clock signals are transmitted to the switch signalrouter and the switch driver, and further configured to control theswitch capacitor converter core.